在mongodb中查询一个文档及其所有匹配条件的子文档(使用spring)

本文介绍了在mongodb中查询一个文档及其所有匹配条件的子文档(使用spring)的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个 MongoDB 存储来自不同传感器的数据.它的结构如下:

I have a MongoDB storing data from different sensors. It has the following structure:

{ "_id" : 1, "sensorName" : "Heart Rate", "samplePeriod" : 1000, "data" : [ { "timestamp" : NumberLong("1483537204046"), "dataPoints" : [ 68 70 ] }, { "timestamp" : NumberLong("1483537206046"), "dataPoints" : [ 68 70 ] } ] } { "_id" : 2, "sensorName" : "Ambient Light", "samplePeriod" : 500, "data" : [ { "timestamp" : NumberLong("1483537204058"), "dataPoints" : [ 56, 54, 54, 54 ] }, { "timestamp" : NumberLong("1483537206058"), "dataPoints" : [ 56, 54, 54, 54 ] } ] }

例如，现在我需要心率" - 包含所有字段及其数据"字段的文档 - 匹配条件时间戳在 1483537204000 和 1483537214000 之间"的子文档.

Now for example i need the "Heart Rate" - document with all of its fields and those of its "data" - subdocuments matching the condition "timestamp between 1483537204000 and 1483537214000".

我已经在另一个问题中得到了关于如何在 mongo shell 中执行此操作的答案.请参阅此代码:

I already got the answer on how to do this in the mongo shell in another Question. See this code:

aggregate([{ $match: { "_id": 1 } }, { "$project": { "_id": 1, "sensorName": 1, "samplePeriod": 1, "data": { "$filter": { "input": "$data", "as": "result", "cond": { $and: [{ $gte: ["$$result.timestamp", 1483537204000] }, { $lte: ["$$result.timestamp", 1483537214000] }] } } } } }])

但是我如何在 java spring-data 中做到这一点?spring-data 中似乎没有像 $filter 这样的东西.有解决办法吗?

But how do I do this in java spring-data? It seems there is nothing like $filter in spring-data. Is there a workaround?

$filter 的效率如何?您能想出一种更有效/更实用的方式在 mongodb 中构建此类数据吗?

How efficient is $filter anyway? Can you think of a more efficient/practical way of structuring this kind of data in mongodb?

提前致谢！

推荐答案

你需要使用spring mongo数据依赖中提供的MongoTemplate.当前发行版本中没有对 $filter 的开箱即用支持.使用 AggressionExpression.在项目中包括以下投影.使用 1.8.5 spring mongo 数据版本.

You'll need to make use of MongoTemplate provided in the spring mongo data dependency. There is no out of box support for $filter in the current release version. Make use of AggressionExpression. Include below projection in project. Use 1.8.5 spring mongo data version.

Aggregation aggregation = newAggregation( match(Criteria.where("_id").is(1)), project( "_id", "sensorName", "samplePeriod").and(new AggregationExpression() { @Override public DBObject toDbObject(AggregationOperationContext aggregationOperationContext) { DBObject filter = new BasicDBObject("input", "$data").append("as", "result").append("cond", new BasicDBObject("$and", Arrays.<Object> asList(new BasicDBObject("$gte", Arrays.<Object> asList("$$result.timestamp", 1483537204000L)), new BasicDBObject("$lte", Arrays.<Object> asList("$$result.timestamp", 1483537214000L))))); return new BasicDBObject("$filter", filter); } }).as("data") ); List<BasicDBObject> dbObjects = monoTemplate.aggregate(aggregation, "collectionname", BasicDBObject.class).getMappedResults();